The US side of Niagara Falls has begun to thaw after being partially frozen from the recent "polar vortex" that affected millions in the US and Canada, Friday, Jan. 10, 2014 in Niagara Falls, NY. (AP Photo/Nick LoVerde)

(Newser)
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Sure, the last two winters have been bitterly cold—but scientists in Zurich and California say this has nothing to do with climate change. In fact, they say extreme cold snaps will become rarer as the climate continues to warm, Eureka Alert reports. The argument goes like this: The Arctic has been warming for decades, and temperatures in mid-latitudes (or temperate zones, where most of us live) vary less often when there's less temperature difference between the tropics and the poles. Think of it this way: If air masses were all the same, there would theoretically be no fluctuation. So, less difference, less fluctuation. The study in the Journal of Climate says climate scenarios support this theory, and simulations by the Intergovernmental Panel on Climate Change came to similar conclusions.

But this doesn't spell an end to extreme temperatures: "Despite lower temperature variance, there will be more extreme warm periods in the future because the Earth is warming," says study leader Tapio Schneider. His team's research runs against another theory—that the warming Arctic is weakening the polar jet stream, a large, powerful wind that's driven by the temperature difference between polar regions and the balmy tropics. A weaker stream is more "wavy," creating more temperature changes in mid-latitudes. But Schneider's not buying it: "The waviness of the jet stream that makes our day-to-day weather does not change much," he says. Another theory holds that smog from Asia is worsening storms over the Pacific Ocean and possibly giving us colder winters, WGBH reports. (Florida apparently doesn't want state environmental workers to use terms like "climate change.")